USPTO Patents Application 10780381

CLAIMS

WHAT' IS CLAIMED

1. A method of limiting reactive torque transmitted
from a set of driven traction wheels to a powertrain
during a sudden braking event, comprising:

slipping a drive connection between the traction
wheels and the powertrain when the sudden braking event
commences, to thereby limit the amount of torque
transmitted from the traction wheels to the powertrain.

2. The method of claim 1, further comprising presetting
a reactive torque value at which the drive connection
begins to slip.

3. The method of claim 1, wherein the slipping step
comprises slipping a plurality of clutch plates when the
reactive torque reaches a preset torque value.

4. The method of claim 2, wherein the slipping step
comprises slipping a plurality of clutch plates when the
reactive torque reaches the preset torque value.

5. The method of claim 1, wherein the slipping step is
commenced in direct response to reactive torque applied
to the drive component .

6. The method of claim 1, wherein the slipping step
comprises using a slip clutch.

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7. The method of claim 1, further comprising:
determining that a sudden braking event is about to

occur;

setting the slip level of the drive component to a
first reactive torque value allowing a first level of
reactive torque to be transmitted from the wheels to the
powertrain; and,

setting a slip level of the drive component to a
second reactive torque value when it has been determined
that a sudden braking event is about to occur.

8. The method of claim 1, further comprising, after
setting the slip level to a second reactive torque
level, resetting the slip level of the drive component
to the first level of torque.

9. The method of claim 9, the slipping step comprises
interposing a slip clutch between the wheels and the
powertrain.

10. A method for controlling a hybrid vehicle
powertrain system during a sudden braking event in which
reactive torque is produced by braking the vehicle's
wheels, comprising the step of limiting the amount of
reactive torque transmitted from the wheels to the
powertrain .

11. The method of claim 10, wherein the torque -limiting
step is performed by slipping a clutch connecting the
wheels with the powertrain.

12. The method of claim 11, wherein the torque limiting
step comprises setting the torque level at which the
clutch begins to slip.

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13. A method for controlling a hybrid vehicle
powertrain system during a sudden braking event in which
excessive driveline torque is produced by rapidly
braking the vehicle's wheels, comprising the steps of:

transmitting negative torque from the wheels
through the driveline component to the powertrain during
normal driving conditions;

limiting the amount of torque transmitted from the
wheels through the driveline component to the powertrain
during a sudden braking event.

14. The method of claim 13, wherein:

the transmitting and limiting steps are
respectively comprise transmitting the positive and
negative torques through a clutch, and

the limiting step further comprises slipping the
clutch when the amount of torque reaches a preselected
value .

15. The method of claim 14, wherein the limiting step
comprises adjusting the clutch to slip in response to
torque equal to or greater than the preselected value.

16. A drive system for a vehicle, comprising:

a powertrain including at least one electric drive
motor,

at least one traction wheel; and,

a driveline including a slip clutch, connecting the
powertrain with the drive wheel, the slip clutch
transmitting positive torque from the powertrain to the
drive wheel during normal driving conditions but

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allowing slipping during a sudden braking event to limit
the amount of torque transmitted from the drive wheel to
the powertrain caused by braking force applied to the
drive wheel .

17. The drive system of claim 16, wherein the slip
clutch includes a plurality of friction plates and
springs for biasing the plates into engagement with each
other.

18. The drive system of claim 17, wherein the biasing
force of the springs is adjustable.

19. The drive system of claim 17, further comprising a
sensor for sensing the commencement of a sudden braking
event, and a controller responsive to the sensor for
adjusting the biasing force of the springs whereby to
adjust the amount of torque transmitted from the wheels
to the powertrain.

20. A hybrid vehicle drive system, comprising:
an internal combustion engine;

an electric drive motor;

at least one traction wheel;

a driveline connecting the traction wheel with the
combination of the internal combustion engine and the
electric drive motor;

a vehicle braking system for applying a brake force
to the traction wheel during a braking event; and,

a control system including a slip clutch for
controlling the torque transmitted from the traction
wheel through the driveline during a sudden braking
event .

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21. The drive system of claim 20, wherein the slip
clutch includes a plurality of clutch plates and springs
for biasing the plates into engagement with each other.

22. The drive system of claim 20, wherein the amount of
torque transmitted by the slip clutch from the drive
wheel to the driveline is adjustable.

23. The drive system of claim 22, wherein the control
system comprises:

at least one sensor producing a signal indicting
the occurrence of a sudden braking event, and

a controller automatically responsive to the sensor
signal for adjusting the slip clutch.

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